请教一个C++的问题是课本上的

已知x=0度，10度，20度或者180度，求sinx,cosx和tanx的值 用C++编程语言

有专门的库函数，名字就是那个，头文件是cmath

#include
#include
using namespace std;
int main()
{
cout << "sin(0)=" << sin(0) << " " << "sin(10)=" << sin(10) << " " << "sin(30)=" << sin(30) << endl;
return 0;
}

供参考：

#include <stdio.h> 
#include <math.h> 
#define PI 3.14159265
int main()
{
    double param;
    while (scanf("%lf", &param) == 1 && param >= 0) {  // 输入非数字 或 负数时，结束输入
        printf("sin(%.0f) = %f.\n", param, sin(param * PI / 180));
        printf("cos(%.0f) = %f.\n", param, cos(param * PI / 180));
        if ((int)param % 90 != 0)
            printf("tan(%.0f) = %f.\n", param, tan(param * PI / 180));
    }
    return 0;
}

供参考：

#include <iostream> 
#include <cmath> 
#define PI 3.14159265

using namespace std;
void calc(int x)
{
    cout << "sin(" << x << ") = " << sin(PI * x / 180) << endl;
    cout << "cos(" << x << ") = " << cos(PI * x / 180) << endl;
    if (x == 0 || (x / 90 % 2 == 0))
        cout << "tan(" << x << ") = " << tan(PI * x / 180) << endl;
}

int main()
{
    calc(0);
    calc(10);
    calc(20);
    calc(180);

    return 0;
}